Abstract : Managing the energy needs of buildings is central. This question is deeply linked with people density in urban area which is still increasing. We are at a turning point: reaching the goal of the low carbon transition. As is known, the reduction of this sector’s carbon footprint entails the reduction of the carbon dioxide emissions that it produces. Consequently, the search of human and technical solutions in a multi-scale and systemic perspective is a central element of this process. First, we observe uses required by sites managers. Second, we aim to show users’ strategies facing automation, both in terms of space occupation and lighting use. Then, we focus on people’s involvement and their behavioural change considering the participatory design of services and systems for smart buildings. Finally, we address the power of collective identity, as a quest of good balance between human action and automation.